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wm-1 autec help

1iwilly

Sr. Member
Dec 7, 2008
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This question if for those who at one time or still have one a WM-1 autec meter I need to adjust the SWR side on my MFJ-259-B which I was lucky enough to have it re-calibrated in February 2024 before they shut down. on the mfj on 40 meters say 7.205 shows a 1.7 SWR the wm-1 shows 1.4 on 20 meters 14.260 mfj 1.1 wm-1 accurate 1.1. I have the manual and I'm a tad confused as to this step #2 do I adjust for a 1.1 not 1.0=meter don't move ?? look at pic Also use the 20 scale or 200 scale because if I adjust on 20 then 200 is off power and swr
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Last edited:

The trimmer capacitors serve to set the 1.0-to-1 reading at 50 ohms. Naturally this is hard to do if your dummy load isn't 50 ohms. That trimmer cap is typically called a compensation capacitor. The idea is to get this setting close with the forward-side meter, then fine-tune its setting on the reverse side by reversing input and output. Naturally a load resistor closest to 50 ohms is the only way to get this right.

If you set any of the power-range trimpots, a droplet of control cleaner on each one before you turn it will improve the odds that the adjustment will remain stable after you set it.

73
 
The trimmer capacitors serve to set the 1.0-to-1 reading at 50 ohms. Naturally this is hard to do if your dummy load isn't 50 ohms. That trimmer cap is typically called a compensation capacitor. The idea is to get this setting close with the forward-side meter, then fine-tune its setting on the reverse side by reversing input and output. Naturally a load resistor closest to 50 ohms is the only way to get this right.

If you set any of the power-range trimpots, a droplet of control cleaner on each one before you turn it will improve the odds that the adjustment will remain stable after you set it.

73
close enough for me
 

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